Hawk Happenings: The Final Results Are In!

November 27, 2020—Posted by Rachael Mady on behalf of Bird Cams Lab

Red-tailed Hawks Change Their Behavior With Temperature, Time of Day, And Age of Nestlings

The Bird Cams Lab community, now 4,393 people strong, came together with scientists this past spring to learn more about the Red-tailed Hawk family seen on the Cornell Lab of Ornithology’s Red-tailed Hawk cam. After proposing and discussing several interesting research questions, the community selected two questions to investigate in “Hawk Happenings”—(1) what is the frequency of certain hawk behaviors, and (2) does this frequency vary with weather?

During May 21–June 14, 2020, 323 people collectively watched almost 265 hours of cam footage in real time and recorded data on six common behaviors: vocalizations, prey delivery, feeding, and three nestling-specific behaviors (flapping, walking, and mantling). Mantling is when a raptor spreads its wings and hunches over prey to prevent others from taking it.

Arthur delivers prey to the nest and one of the hawk nestlings displays mantling behavior. Mantling is when a bird arches its body and spreads its wings to shield prey from other birds or animals that might be interested. 

After June 14, when all of the nestlings had fledged, or flown from the nest, the community explored the data via online interactive graphs, online forums, and a live webinar to discuss patterns seen in the data with the Bird Cams Lab staff. One pattern that stood out and sparked discussion was that while the likelihood of a feeding was relatively high and didn’t vary with the time of day, the likelihood of a prey delivery did (Figure 1, Figure 2). The likelihood of a prey delivery increased in the early morning, decreased around midday, and increased again in the late afternoon.

Percent Chance Of Feeding Remained Relatively High All Day

A bar chart showing that the percent chance of a feeding is about 35-75% throughout most of the day.Figure 1. A bar chart in which the height of each bar represents the percentage chance that there is a feeding during each daylight hour. Each day was split into 1-hour intervals from 5:00 A.M. to 8:00 P.M.

Percent Chance Of Prey Delivery Peaked In The Morning And Late Afternoon

A bar chart showing the percent chance of a prey delivery across the hours of a day. The highest percent chance is about 75% in hour 7 and 8.Figure 2. A bar chart in which the height of each bar represents the percentage chance that there is a prey delivery during each daylight hour. Each day was split into 1-hour intervals from 5:00 A.M. to 8:00 P.M.

In the forums and in the live webinar, the community noted that this pattern reflected their understanding of the Red-tailed Hawks and the birds they would see at their own feeders.

From my observations of the adults, both on and off the nest cam, they appear to be most active in the early morning and late afternoon. –BirdieL

I have observed over the years that songbirds and small rodents are very active at my feeders in the early morning. It makes sense that adults bring more prey to the nest during the early mornings…because there is more prey readily available during those hours. –Chirpiesmom

…prey delivery is reflective of prey availability and skill of adults, and they are just in constant delivery mode and not much to do with how hungry the young are… –Fiona

We now bring Hawk Happenings to a close as the second co-created investigation with the Red-tailed Hawks cam (the first was Hawk Talk). The Bird Cams Lab community, together with scientists, uncovered patterns either undocumented or sparsely documented in the scientific literature, and we hope can inform future work on these birds as well as other raptors.

To learn more,, future work will need to look at multiple nests (increasing the sample size) and over a longer time period (increasing the sample period). As many people during the live webinar pointed out, Hawk Happenings looked at one nest during one breeding season. We’ve just scratched the surface!

Thank you to everyone who participated in Hawk Happenings. Whether you helped us come up with the questions, collected data, explored the data, or reviewed the final report, you helped shape this investigation. Thanks to this team effort, we now know more than ever before about the behavior of the Red-tailed Hawks that nest over Cornell University’s athletic fields.

  • If you’d like to see more of the patterns the community uncovered from the raw data or the results from the exploratory statistical modeling, check out the Final Report.
  • If you’re interested in accessing the full dataset, email birdcams@cornell.edu.
  • If you’re ready for the next investigation, jump right in! We’ll be teaming up with Cornell Lab researcher Dr. Eliot Miller to study the birds on the Panama Fruit Feeder cam. Sign up and take a survey today.

If you have any additional takeaways, thoughts, or questions about this investigation, please post below!